Wireless networks rely on a large number of individual base stations or cells to provide high capacity wireless services over large coverage areas, such as market areas (e.g., cities), surrounding residential areas (e.g., suburbs, counties), highway corridors and rural areas. Continuous radio connectivity across these large coverage areas is accomplished via user mobility from one base station to others as the user traverses the network's operating area. High reliability mobility in mobile wireless networks minimizes the number of dropped calls or other abnormal discontinuations of radio service to the supported users.
Modern broadband wireless access technologies, such as the Universal Mobile Telecommunication System (UMTS), High Speed Packet Access (HSPA), Long Term Evolution (LTE), and so on, rely on the reuse of a finite number of codes, which are used by mobile devices to differentiate signals originating from different base stations in a network. These codes, such as 3G scrambling codes or 4G PCI codes, are reused multiple times across wide area networks, often with the same code being allocated to multiple base stations in the networks.
Suboptimal allocation of these codes may result in insufficient radio frequency isolation between two base stations that utilize the same code, leading to problems with network performance and high reliability mobility within the network. For example, suboptimal allocation of codes may lead to code ambiguities and/or excessive interference to mobile devices operating in areas where signals from two or more base stations utilizing the same code are received at sufficient strength and confusion and/or excessive interference at the mobile device.
The common reuse of codes include code reuse planning prior to network deployment, which attempts to minimize code reuse conflicts and ensure sufficient reuse distances between two or more wireless base stations utilizing the same code. Often, reuse planning relies on radio frequency path loss and inter-cell radio frequency isolation estimates, which can be erroneous and misleading when compared to the actual isolation between actual cells. In addition, reuse planning is often insufficient in allocating codes during network evolution and/or the addition of new cells into an established network, resulting in increased code reuse conflicts over time and degraded network performances, among other drawbacks.